19979438866 has 12 divisors (see below), whose sum is σ = 31629500622. Its totient is φ = 9463944384.

The previous prime is 19979438807. The next prime is 19979438879. The reversal of 19979438866 is 66883497991.

It can be written as a sum of positive squares in only one way, i.e., 12801791025 + 7177647841 = 113145^2 + 84721^2 .

It is a junction number, because it is equal to n+sod(n) for n = 19979438795 and 19979438804.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 13835455 + ... + 13836898.

Almost surely, 2^19979438866 is an apocalyptic number.

19979438866 is a deficient number, since it is larger than the sum of its proper divisors (11650061756).

19979438866 is a wasteful number, since it uses less digits than its factorization.

19979438866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27672393 (or 27672374 counting only the distinct ones).

The product of its digits is 141087744, while the sum is 70.

The spelling of 19979438866 in words is "nineteen billion, nine hundred seventy-nine million, four hundred thirty-eight thousand, eight hundred sixty-six".